SKN module failure

[Tom Henton]

I’ve got a starting problem with my TJ. Its been diagnosed, the SKN module isn’t responding.

 

The garage isn’t able to recode, can anybody help me??

Main dealer is saying they can do it but I have to be prepared to stomach a £1000 bill

[V]

As it's a starting problem, I assume you mean the Sentry Key Immobiliser Module (SKIM).

 

Try this first, it can't hurt and worked for me a few weeks ago.

1. If your Jeep has a factory alarm system, disconnect the car battery from the vehicle so no electrical power is going into the car.
2. Turn the ignition key to try to start the car, it won't, it just helps discharge some circuits.
3. Leave the battery disconnected overnight to discharge the alarm system fully.
4. Reconnect the battery and try to start the Jeep

 

The SKIM was standard on EU models but optional on US models. Your Jeep can be setup to be SKIMless but that will affect your insurance and you still need someone with a DRB3 or StarScan reprogramming tool to make the Jeep forget the SKIM.

 

I remember being told about some early TJs having an electronic security module somewhere on the engine compartment bulkhead which is a big job to correct if the Jeep cannot be started, but I don't know much else about it. For later TJs and other Jeeps the SKIM is on the steering column. Ask the dealer what is being done for the £1000.

 

Can you describe what happens when your Jeep doesn't start? Are you certain it is the SKIM? A common problem on TJ and face lift XJ is the ignition switch actuator pin breaking or wearing with age. This is an easy and cheap DIY fix. Mine wore out in 2019 but the supplier sent me a broken part that had a shorter pin than the one I removed. Easily spotted, if you know what it should look like to begin with. The Dorman branded replacement part is OK, but the packaging is crap which is why some new Dorman actuator pins are broken when unwrapped. I also replaced my switch contact blocks just to be sure.

Edited February 3, 2022 by V
Accidentally deleted a line and forgot a link

[JimC]

3 hours ago, V said:

As it's a starting problem, I assume you mean the Sentry Key Immobiliser Module (SKIM).

 

Try this first, it can't hurt and worked for me a few weeks ago.

1. If your Jeep has a factory alarm system, disconnect the car battery from the vehicle so no electrical power is going into the car.
2. Turn the ignition key to try to start the car, it won't, it just helps discharge some circuits.
3. Leave the battery disconnected overnight to discharge the alarm system fully.
4. Reconnect the battery and try to start the Jeep

 

The SKIM was standard on EU models but optional on US models. Your Jeep can be setup to be SKIMless but that will affect your insurance and you still need someone with a DRB3 or StarScan reprogramming tool to make the Jeep forget the SKIM.

 

I remember being told about some early TJs having an electronic security module somewhere on the engine compartment bulkhead which is a big job to correct if the Jeep cannot be started, but I don't know much else about it. For later TJs and other Jeeps the SKIM is on the steering column. Ask the dealer what is being done for the £1000.

 

Can you describe what happens when your Jeep doesn't start? Are you certain it is the SKIM? A common problem on TJ and face lift XJ is the ignition switch actuator pin breaking or wearing with age. This is an easy and cheap DIY fix. Mine wore out in 2019 but the supplier sent me a broken part that had a shorter pin than the one I removed. Easily spotted, if you know what it should look like to begin with. The Dorman branded replacement part is OK, but the packaging is crap which is why some new Dorman actuator pins are broken when unwrapped. I also replaced my switch contact blocks just to be sure.

Would the old three turns off the ignition key display faults like this?

insert the Key in the ignition, and turning it 'on-off' 3 times and on the last turn, leave it in the 'on' position. This should show the stored trouble codes on the dash display.

These will be the ODBII codes and have a pen and paper ready as they only stay on the odometer display for a couple of seconds

 

 

 

Found this on the web as well - https://www.jeepgarage.org/threads/get-odbii-codes-by-key-turns.46434/

 

Customer Key Programming
You can program new keys to the system if you have two
valid keys by doing the following:
1. Cut the additional Sentry Key Transponder blank(s) to
match the ignition switch lock cylinder key code.
2. Insert the first valid key into the ignition switch and
turn the ignition switch ON for at least 3 seconds but no
longer than 15 seconds. Turn the ignition switch OFF and
remove the first key.
3. Insert the second valid key and turn the ignition
switch ON within 15 seconds. After ten seconds, a chime
will sound and the SKIS indicator light will begin to
flash. Turn the ignition switch OFF and remove the
second key.
4. Insert a blank Sentry Key into the ignition switch and
turn the ignition switch ON within 60 seconds. After 10
seconds, a single chime will sound. The SKIS indicator
light will stop flashing, turn on for 3 seconds; then turn off.
The new Sentry Key has been programmed. Repeat this
process to program up to a total of 8 keys.

[UKTJ]

4 hours ago, JimC said:

Would the old three turns off the ignition key display faults like this?

insert the Key in the ignition, and turning it 'on-off' 3 times and on the last turn, leave it in the 'on' position. This should show the stored trouble codes on the dash display.

These will be the ODBII codes and have a pen and paper ready as they only stay on the odometer display for a couple of seconds

 

 

 

Found this on the web as well - https://www.jeepgarage.org/threads/get-odbii-codes-by-key-turns.46434/

 

Customer Key Programming
You can program new keys to the system if you have two
valid keys by doing the following:
1. Cut the additional Sentry Key Transponder blank(s) to
match the ignition switch lock cylinder key code.
2. Insert the first valid key into the ignition switch and
turn the ignition switch ON for at least 3 seconds but no
longer than 15 seconds. Turn the ignition switch OFF and
remove the first key.
3. Insert the second valid key and turn the ignition
switch ON within 15 seconds. After ten seconds, a chime
will sound and the SKIS indicator light will begin to
flash. Turn the ignition switch OFF and remove the
second key.
4. Insert a blank Sentry Key into the ignition switch and
turn the ignition switch ON within 60 seconds. After 10
seconds, a single chime will sound. The SKIS indicator
light will stop flashing, turn on for 3 seconds; then turn off.
The new Sentry Key has been programmed. Repeat this
process to program up to a total of 8 keys.

Can’t find it now, but I seem to recall seeing something similar but with a note you could not code your own keys in export TJs.  I will keep trying to see if I can find it.

[UKTJ]

OK, not sure if I will get into trouble for posting this link, but I am only doing so to try and help.  Below is a link to a thread on SKIM / SKIS on a US based TJ specific forum.  The opening post includes the Customer Learn process, but does say it only works on US domestic TJs.  Hopefully there may be some useful non-US specific in there that will help...

 

https://wranglertjforum.com/threads/skis-skim-sentry-key-programming.16848/

[JimC]

47 minutes ago, UKTJ said:

OK, not sure if I will get into trouble for posting this link, but I am only doing so to try and help.  Below is a link to a thread on SKIM / SKIS on a US based TJ specific forum.  The opening post includes the Customer Learn process, but does say it only works on US domestic TJs.  Hopefully there may be some useful non-US specific in there that will help...

 

https://wranglertjforum.com/threads/skis-skim-sentry-key-programming.16848/

[frosty]

if you get no joy, try Phil at Hargreaves MOT, 01274 569262 he is the private jeep specialist near Bradford, he is the only guy i trust to work on all my jeeps, he fixed a Skim problem on my TJ, after i flattened the battery and jump started it. He is a true Jeep specialist. 

[Ludders]

Have you tried any of the ECU repairers?

Local to me are:

ECU Technologies

ATC (formerly ATP Electronics)

 

They may need the ECU and SKM module but they may be able to remove immobiliser. 

[frosty]

my TJ has a USA ECU, so no problems with the Skim. 

[V]

This thread has made me consider acquiring a used DRB3 from the USA. These tools are still changing hands for $1700-$2200 on eBay and the buyer has no idea what updates have been applied or if it even works. It seems Chrysler was using software to protect it's maintenance business long before John Deere.